U.S. patent application number 12/609176 was filed with the patent office on 2011-05-05 for integrated acoustic horn and lead frame.
This patent application is currently assigned to Avago Technologies Wireless IP (Singapore) Pte. Ltd.. Invention is credited to Atul Goel, Timothy Leclair.
Application Number | 20110103632 12/609176 |
Document ID | / |
Family ID | 43829015 |
Filed Date | 2011-05-05 |
United States Patent
Application |
20110103632 |
Kind Code |
A1 |
Leclair; Timothy ; et
al. |
May 5, 2011 |
INTEGRATED ACOUSTIC HORN AND LEAD FRAME
Abstract
A device for manipulating acoustic signals includes a transducer
die and a horn. The transducer die is attached to a lead frame and
configured to convert between electrical energy and the acoustic
signals, the transducer die having a transducer membrane. The horn
is integrally connected with the lead frame, the horn extending
from the lead frame and having a throat positioned adjacent to the
transducer membrane and a mouth opening at an opposite end of the
horn from the throat.
Inventors: |
Leclair; Timothy; (Longmont,
CO) ; Goel; Atul; (Fort Collins, CO) |
Assignee: |
Avago Technologies Wireless IP
(Singapore) Pte. Ltd.
Singapore
SG
|
Family ID: |
43829015 |
Appl. No.: |
12/609176 |
Filed: |
October 30, 2009 |
Current U.S.
Class: |
381/340 |
Current CPC
Class: |
H01L 2224/48247
20130101; H01L 2224/48091 20130101; H01L 2924/3011 20130101; H01L
2924/1461 20130101; H01L 2924/1461 20130101; H01L 2224/45124
20130101; H01L 2224/48091 20130101; H01L 2224/45124 20130101; H01L
2924/3011 20130101; H04R 1/30 20130101; H01L 2924/00 20130101; H01L
2924/00 20130101; H01L 2924/00 20130101; H01L 2924/00014
20130101 |
Class at
Publication: |
381/340 |
International
Class: |
H04R 1/20 20060101
H04R001/20 |
Claims
1. A device for manipulating acoustic signals, the device
comprising: a transducer die attached to a lead frame and
configured to convert between electrical energy and the acoustic
signals, the transducer die comprising a transducer membrane; and a
horn integrally connected with the lead frame, the horn extending
from the lead frame and comprising a throat positioned adjacent to
the transducer membrane and a mouth opening at an opposite end of
the horn from the throat.
2. The device of claim 1, wherein the transducer die comprises a
micro electro-mechanical system (MEMS) transducer.
3. The device of claim 1, wherein the transducer die is attached to
a top surface of the lead frame and the horn extends from a bottom
surface of the lead frame, the lead frame defining an aperture
between the transducer membrane and the throat of the horn.
4. The device of claim 3, further comprising: a lid connected to
the top surface of the lead frame, the lid and a base portion of
the horn defining a cavity, wherein the transducer die is
positioned within the cavity.
5. The device of claim 4, wherein the cavity is hermetically
sealed.
6. The device of claim 1, wherein the horn comprises plastic
transfer molded through a portion of the lead frame and extending
from the lead frame to the mouth of the horn.
7. The device of claim 6, wherein at least a portion of a
cross-section of the horn has a widening shape.
8. The device of claim 6, wherein the molded plastic comprises at
least one of liquid crystal polymer (LCP), polybutylene
terephthalate (PBT), polypropylene (PP), polyphthalamide (PPA).
9. The device of claim 6, wherein the lead frame defines at least
one port through which the transfer molded plastic extends,
knitting together the lead frame and the horn.
10. The device of claim 1, wherein the transducer die comprises at
least one contact pad connected to the lead frame via at least one
corresponding bonding wire.
11. The device of claim 1, further comprising: a screen covering
the mouth of the horn and configured to protect the transducer die
from at least one of debris, contaminates, and moisture.
12. A device comprising: a lead frame; an acoustic horn comprising
a base portion integrated with the lead frame and a protruding
portion extending from the lead frame, the acoustic horn defining a
first aperture corresponding to a horn throat and a second aperture
corresponding to a horn mouth; and an transducer die positioned on
the lead frame adjacent to the first aperture of the acoustic horn,
and configured to convert between electrical energy and acoustic
signals, wherein the acoustic horn adjusts a radiation pattern of
the acoustic signals.
13. The device of claim 12, wherein the transducer die comprises a
micro electro-mechanical system (MEMS) transducer.
14. The device of claim 12, further comprising: a lid connected to
the base portion of the acoustic horn and defining a cavity between
an inner surface of the lid and a top surface of the base portion,
the transducer die being positioned within the cavity.
15. The device of claim 14, wherein the first aperture has a
smaller diameter than the second aperture.
16. The device of claim 14, further comprising: a screen covering
the second aperture of the acoustic horn and configured to protect
the transducer die from at least one of debris, contaminates and
moisture.
17. A packaged semiconductor device comprising: a lead frame
defining an aperture; a transfer molded acoustic horn comprising a
base portion integrated with the lead frame and a protruding
portion extending from the lead frame, a throat of the acoustic
horn being substantially aligned with the aperture of the lead
frame; a lid connected to the integrated acoustic horn and lead
frame to form a cavity; and a transducer die positioned in the
cavity on the lead frame, the transducer die comprising a micro
electro-mechanical system (MEMS) transducer configured to convert
between electrical energy and acoustic signals, the MEMS transducer
having a membrane and a back-etched portion substantially aligned
with the aperture of the lead frame and the throat of the acoustic
horn.
18. The device of claim 17, wherein the acoustic horn adjusts a
radiation pattern of the acoustic signals.
19. The device of claim 17, wherein the acoustic horn provides
impedance matching for the acoustic signals.
20. The device of claim 17, further comprising: a screen covering a
mouth of the acoustic horn, opposite the throat of the acoustic
horn, the screen protecting the transducer die from at least one of
debris, contaminates and moisture.
Description
BACKGROUND
[0001] Transducers incorporated in various electronic devices
include semiconductor integrated circuits for converting electrical
signals into acoustic signals (e.g., acoustic waves) and/or
acoustic signals into electrical signals. The conversion is useful
in numerous applications, such as signal filtering, signal
isolation, sensing, mechanical actuation, etc.
[0002] In order to generate ultrasonic acoustic signals, in
particular, the transducers must be quite small. For example, micro
electro-mechanical system (MEMS) transducers may be used as
ultrasonic transducers. MEMS transducers are typically more
efficient than traditional transducers. However, due to their small
size, MEMS transducers have lower effective output power, lower
sensitivity and/or broader (less focused) radiation patterns.
Further, such transducers may be included in semiconductor
packages, including lead frames to provide easier connections with
other circuits.
SUMMARY
[0003] In a representative embodiment, a device for manipulating
acoustic signals includes a transducer die attached to a lead frame
and configured to convert between electrical energy and the
acoustic signals, the transducer die having a transducer membrane.
The device further includes a horn integrally connected with the
lead frame, the horn extending from the lead frame and having a
throat positioned adjacent to the transducer membrane and a mouth
opening at an opposite end of the horn from the throat.
[0004] In another representative embodiment, a device includes a
lead frame, an acoustic horn and a transducer die. The acoustic
horn includes a base portion integrated with the lead frame and a
protruding portion extending from the lead frame, the acoustic horn
defining a first aperture corresponding to a horn throat and a
second aperture corresponding to a horn mouth. The transducer die
is positioned on the lead frame adjacent to the first aperture of
the acoustic horn, and configured to convert between electrical
energy and acoustic signals. The acoustic horn adjusts a radiation
pattern of the acoustic signals.
[0005] In another representative embodiment, a packaged
semiconductor device includes a lead frame defining an aperture, a
transfer molded acoustic horn, a lid and a transducer die. The
transfer molded acoustic horn includes a base portion integrated
with the lead frame and a protruding portion extending from the
lead frame, a throat of the acoustic horn being substantially
aligned with the aperture of the lead frame. The lid is connected
to the integrated acoustic horn and lead frame to form a cavity.
The transducer die is positioned in the cavity on the lead frame,
the transducer die including a MEMS transducer configured to
convert between electrical energy and acoustic signals, the MEMS
transducer having a membrane and a back-etched portion
substantially aligned with the aperture of the lead frame and the
throat of the acoustic horn.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] The example embodiments are best understood from the
following detailed description when read with the accompanying
drawing figures. It is emphasized that the various features are not
necessarily drawn to scale. In fact, the dimensions may be
arbitrarily increased or decreased for clarity of discussion.
Wherever applicable and practical, like reference numerals refer to
like elements.
[0007] FIG. 1 is a cross-sectional diagram illustrating an
integrated lead frame and acoustic horn packaging structure for a
transducer, according to a representative embodiment.
[0008] FIGS. 2A through 2D are perspective views illustrating
integrated lead frame and acoustic horn packaging, according to a
representative embodiment.
[0009] FIG. 3 is a flow diagram illustrating a process for
fabricating an integrated lead and acoustic horn package, according
to a representative embodiment.
[0010] FIG. 4 is a perspective view illustrating integrated lead
frame and acoustic horn packaging during the fabrication process,
according to a representative embodiment.
DETAILED DESCRIPTION
[0011] In the following detailed description, for purposes of
explanation and not limitation, representative embodiments
disclosing specific details are set forth in order to provide a
thorough understanding of the present teachings. However, it will
be apparent to one having ordinary skill in the art having had the
benefit of the present disclosure that other embodiments according
to the present teachings that depart from the specific details
disclosed herein remain within the scope of the appended claims.
Moreover, descriptions of well-known apparatuses and methods may be
omitted so as to not obscure the description of the representative
embodiments. Such methods and apparatuses are clearly within the
scope of the present teachings.
[0012] Generally, horns may be used to amplify acoustic signals,
making them louder, as indicated by the incorporation of horns in
various musical instruments and early hearing aids, for example.
Horns may also be used to manipulate radiation patterns of acoustic
emitters, generally referred to as beam forming or beam shaping,
thus affecting dispersion of the acoustic signals. In addition,
horns may provide impedance matching, rendering the acoustic
emitter more compatible with the medium through which the acoustic
signals travel. The acoustic emitters may include, for example,
ultrasonic transducers and micro electro-mechanical system (MEMS)
transducers. As discussed below, various embodiments make use of
transfer molded lead frame semiconductor packaging technology to
provide an integrated horn and lead frame, which protects the
transducer (e.g., MEMS microchip) as well as amplifies the acoustic
signals, manipulates the associated radiation pattern and/or
provide impedance matching, for more efficient implementation.
[0013] FIG. 1 is a cross-sectional diagram illustrating a
semiconductor lead frame package, including an integrated lead
frame and acoustic horn assembly for an acoustic transducer, such
as an ultrasonic or MEMS transducer integrated circuit, according
to a representative embodiment.
[0014] As shown in FIG. 1, lead frame package 100 includes lead
frame 110 integrally attached to acoustic horn 120. The acoustic
horn 120 includes a base portion 122 that abuts a first side (e.g.,
bottom side) 115 of the lead frame 110 and a protruding portion 124
that extends from the base portion 122 along a center axis 125 in a
direction substantially perpendicular to the lead frame 110. In a
representative embodiment, the acoustic horn 120 is formed from
plastic transfer molded to the lead frame 110, discussed below.
[0015] In the depicted embodiment, the protruding portion 124 has a
generally hyperbolic or exponential cross-sectional shape, such
that an inner dimension of the acoustic horn 120 extends outwardly
from an inner aperture or throat 126 to a flared outer aperture or
mouth 127. For example, the throat 126 may be circular with a
diameter of about 2 mm and the mouth 127 may likewise be circular
with a diameter of about 8 mm. However, the sizes and shapes of the
acoustic horn 120 and corresponding throat 126 and mouth 127, as
well as the respective configurations of the base portion 122 and
the protruding portion 124, may vary to provide unique benefits for
any particular situation or to meet application specific design
requirements of various implementations, as would be apparent to
one skilled in the art. For example, the cross-sectional shape of
the protruding portion 124 may be substantially conical, tubular,
rectangular or trapezoidal, without departing from the scope of the
present teachings.
[0016] As stated above, the lead frame 110 is integrally attached
to the acoustic horn 120. For example, in an embodiment, the lead
frame 110 includes one or more attachment ports, indicated by
representative ports 118 and 119, which align with corresponding
projections 128 and 129 from an adjacent or top surface of the base
portion 122 in order to knit together and integrally attach the
lead frame 110 and the acoustic horn 120. The ports 118/119 and
corresponding projections 128/129 may be substantially circular in
shape, as shown for example in FIG. 4 (discussed below), although
other numbers and shapes of ports and projections may be included
without departing from the scope of the present teachings. Further,
in various embodiments, the lead frame 110 and the plastic acoustic
horn 120 may be integrally attached using additional or alternative
means, such as adhesive bonding, for example.
[0017] The lead frame package 100 further includes a transducer die
140 attached to a second side (e.g., top side) 117 of the lead
frame 110, and a cap or lid 150 that is connectable to the
integrated assembly of the lead frame 110 and the acoustic horn
120. For example, the lid 150 may be press fitted to the
corresponding edges of the base portion 122 of the acoustic horn
120. Also, an adhesive epoxy, for example, may be applied to a seam
between the lid 150 and the corresponding edges of the base portion
122, in order to attach and/or hermetically seal the lid 150 and
the integrated assembly of the lead frame 110 and the acoustic horn
120. Other attachment and/or sealing means may be incorporated
without departing from the scope of the present teachings. The lid
150 may also be formed to include slots (not shown) corresponding
to the terminal leads of the lead frame 110, of which only terminal
lead 111 is shown in FIG. 1, enabling the terminal leads to extend
from the lead frame package 100 to be connected to external
circuits, for example.
[0018] In an embodiment, the lid 150 defines a cavity 155 between
an inner surface 153 of the lid 150 and the second side 117 of the
lead frame 110 and/or the base portion 122 of the acoustic horn
120. The transducer die 140 may be attached to the lead frame 110
using an attach material, such as a non-conductive adhesive epoxy,
within the cavity 155 defined by the lid 150. The transducer die
140 is configured to convert between electrical energy and the
acoustic signals (e.g., ultrasonic acoustic signals). The acoustic
horn 120 provides better impedance matching, acoustic amplification
and/or radiation pattern control than the transducer die 140 alone,
in transmit and/or receive modes. For example, a large transducer
die 140 typically has a relatively narrow beam angle, while a small
transducer die 140 typically has a relatively wide beam angle. The
size and shape of the acoustic horn 120 is able to manipulate these
beam angles into desired patterns or beam shapes. In addition, the
acoustic horn 120 is able to improve mismatches between the
transducer die 140 and the propagation medium (e.g., air).
[0019] In an embodiment, the transducer die 140 includes an
acoustic transducer having a suspended portion or membrane 141. The
membrane 141 exposed to the exterior through back-etched portion
145 of the semiconductor chip and an aperture 116 in the lead frame
110, which are substantially aligned with the throat 126 of the
acoustic horn 120. The back-etched portion 145 may be formed in a
substrate, which may include various types of materials, such as
glass, sapphire, alumina, or the like, or any semiconductor
material, such as silicon, gallium arsenide (GaAs), indium
phosphide (InP), or the like, by machining or by chemically etching
the substrate using photolithography, although various alternative
techniques may be incorporated. In an embodiment, by being formed
on the bottom of the lead frame 110, the acoustic horn 120 provides
low acoustic loss based on the inverted mounting of the transducer
die 140 through the back-etched portion 145 and the aperture
116.
[0020] As stated above, the acoustic transducer may be a MEMS
transducer, for example, for converting electronic signals to
acoustic signals (e.g., ultrasonic signals) and/or for converting
acoustic signals to electronic signals. In an embodiment, the
acoustic transducer may be a thin film piezoelectric device and may
include a stacked structure of a bottom electrode, a piezoelectric
film, and a top electrode. The piezoelectric film can be formed
from a material, such as aluminum nitride, lead zirconate titanate
(PZT), or other film compatible with semiconductor processes. In
another embodiment, acoustic transducer may include a piezoelectric
crystal. The bottom and top electrodes may be formed from a metal
compatible with semiconductor processes, such as molybdenum,
tungsten, aluminum or a combination thereof.
[0021] The lead frame 110 is formed from an electrically conductive
material, such as various metals and metal alloys, including
copper, nickel, aluminum, brass, copper/zinc alloys, and the like,
or a combination thereof, for example. The material may be etched
to form separate conductors and terminal leads 111-114 (e.g., shown
in FIG. 2A), as well as other features, such as ports 116 and 118.
The acoustic horn 120 is formed from a non-conductive material,
such as various plastics or polymers, including liquid crystal
polymer (LCP), polybutylene terephthalate (PBT), polypropylene
(PP), polyphthalamide (PPA), and the like, for example. The
acoustic horn 120 may be molded in the shape depicted, for example,
in FIG. 1, using transfer molding or other molding techniques, to
support different environmental and operating conditions.
[0022] In an embodiment, a protective mesh or barrier screen 121
covers the mouth 127 of the acoustic horn 120. The screen 121
includes a pattern of apertures (not shown) for communicating
acoustic signals between the acoustic transducer of transducer die
140 and the exterior of lead frame package 100. For example, each
of the apertures of the screen 121 may be substantially smaller
than the size of aperture 116 in the lead frame 110. The screen 121
may include acoustically transparent solid material to allow
acoustic signals to exit and/or enter the aperture 116, but
limiting debris, contaminates and/or moisture that can enter the
aperture 116. In an embodiment, the screen 121 is positioned
directly in the mouth 127 of the protruding portion 124. The screen
121 may be applied after assembling the lead frame package 100,
including attachment of the lid 150.
[0023] FIGS. 2A through 2D are perspective views illustrating
integrated lead frame and acoustic horn packaging, according to a
representative embodiment.
[0024] FIG. 2A, in particular, is a bottom perspective view of the
lead frame package 100, looking into the mouth 127 of the acoustic
horn 120 defined by the outer edge of the protruding portion 124,
according to a representative embodiment. As discussed above, in
the depicted embodiment, the protruding portion 124 has a widening
cross-sectional shape, which may include substantially conical,
exponential, hyperbolic shapes, for example, with a circular mouth
127 and a smaller circular throat 126, which is shown symmetrically
centered within the wider diameter mouth 127. The membrane 141 (not
shown) of the transducer die 140 is positioned at the throat
126.
[0025] Corner portions of the base portion 122 of the acoustic horn
120 are shown beneath the protruding portion 124, where the base
portion 122 is substantially square in shape. Bottom edges of the
lid 150 (in the attached position) are shown surrounding the outer
periphery of the base portion 122. The terminal leads 111-114 of
the lead frame 110 extend from the combined acoustic horn 120 and
lid 150. However, the sizes and shapes of the protruding portion
124, the base portion 122 and the lid 150 may vary to provide
unique benefits for any particular situation or to meet application
specific design requirements of various implementations, as would
be apparent to one skilled in the art.
[0026] FIG. 2B is a side perspective view of the lead frame package
100, taken along line b-b' of FIG. 2A, according to a
representative embodiment. FIG. 2B shows the protruding portion 124
extending from the lid 150 centered on axis 125. Only terminal lead
114 of the lead frame 110 is visible from the present perspective.
FIG. 2C is another side perspective view of the lead frame package
100, according to a representative embodiment. FIG. 2C also shows
the protruding portion 124 extending from the lid 150 centered on
axis 125. The outer ends of the terminal leads 111-114 of the lead
frame 110 are visible from the present perspective where they pass
through the pre-formed slots of the lid 150.
[0027] FIG. 2D is a top perspective view of the lead frame package
100, according to a representative embodiment. FIG. 2D shows the
top of the lid 150 in its attached position to the integrated
assembly of the lead frame 110 and the acoustic horn 120, forming a
cavity to house for the transducer 140 (not shown in FIG. 2D). The
terminal leads 111-114 of the lead frame 110 extend from the cap
150 through the corresponding pre-formed slots from the present
perspective.
[0028] FIG. 3 is a flow diagram illustrating a process for
fabricating an integrated lead and acoustic horn package, according
to a representative embodiment. The depicted embodiment
incorporates a reel-to-reel process, as an example, in which a
string of lead frame packages are fabricated according to the
various process steps and then separated into individual packaged
units. It is understood, however, that other types of fabrication
processes may be incorporated without departing from the scope of
the present teachings.
[0029] For example, FIG. 4 is a top perspective view illustrating
integrated lead and acoustic horn packaging during a reel-to-reel
fabrication process, according to a representative embodiment, in
which a string of lead frame packages, e.g., representative lead
frame packages 100a and 100b, are still connected to reel-to-reel,
lead frame alignment tracks 180 and 190. The lead frame packages
100a and 100b are in different stages of fabrication, where lead
frame package 100a is shown before attachment of the lid 150 and
lead frame package 100b is shown after attachment of the lid 150.
The lead frame material (discussed below) includes the lead frame
alignment tracks 180 and 190, which have representative guide holes
181 and 191, respectively. The guide holes 181 and 191, along with
other evenly spaced guide holes, are physically engaged by
revolving reels to methodically advance the lead frame alignment
tracks 180 and 190 (and thus the frame packages 100a and 100b) in
the direction indicated by arrow D in the course of the
reel-to-reel fabrication process. Accordingly, each of the frame
packages 110a and 110b is fabricated in consecutive process steps,
discussed below with reference to FIG. 3, as the lead frame
alignment tracks 180 and 190 advance.
[0030] Referring to FIG. 3, the lead frame is first etched in block
310 to provide a desired pattern of conductors, terminal leads and
other features. The etching may include chemical etching using
photolithography, for example, although various alternative
techniques may be incorporated. Referring to FIG. 4, the terminal
leads 111-114, as well as the depicted illustrative conductor
pattern and ports 118/119, are formed during the etching process.
In addition, aperture 116 (not shown in FIG. 4) is formed during
the etching process in the vicinity of where the transducer die 140
is to be bonded to the lead frame 110. In block 312, the etched
lead frame is plated for wirebonding, for example, using an
optimized plating material, such as nickel and/or gold, to permit
gold or aluminum wirebond attachment. The wirebonds provide the
electrical interconnections from the MEMS to the lead frame
package.
[0031] A molding operation is performed on the plated lead frame in
block 314. The molding operation includes placing the plated lead
frame 110 in a transfer mold previously formed to define the shape
of the acoustic horn 120, including corresponding base and
protruding portions 122 and 124. A polymer, e.g., LCP, PBT, PP, or
PPA, is then transfer molded, for example, to encapsulate the
plated lead frame 110 and to simultaneously form the acoustic horn
120. The polymer is typically a solid at room temperature, and
melted prior to transfer to the mold. The shape of the acoustic
horn 120 is defined by the shape of the machined transfer mold. The
cooled (after melting) mold plastic will assume the horn shape
within the transfer mold. Accordingly, the plastic acoustic horn
120, e.g., as shown in FIG. 1, is integrally formed to surround the
lead frame 110 during the molding operation. Referring to FIG. 4,
the top surface of the base portion 122 of the acoustic horn 120 is
visible, while the protruding portion 124 (not shown) protrudes
from the bottom side of the base portion 122. The projections 128
and 129 pass through the corresponding ports 118 and 119, which
align and physically attach the acoustic horn 120 with the lead
frame 110.
[0032] In block 316, the transducer die 140 is attached to the lead
frame 110, e.g., on a previously formed die pad (not shown). Other
components may be attached to the lead frame 110 in block 316, as
well. The transducer die 140 may be attached using various
techniques, such as adhesive bonding, soldering, ultrasonic
welding, and the like. Wirebonding is performed in block 318, where
representative bonding wires 141 and 144 are connected between pads
(not shown) on the transducer die 140 and the conductor pattern
(e.g., connected to lead terminals 111 and 114, respectively) of
the lead frame 110. The pads on the transducer die 140 may be top
pads, for example, electrically connected to the top electrodes of
the acoustic transducer of the transducer die 140. In an
embodiment, the transducer die 140 is previously fabricated for
attachment to the lead frame 110, including etching of the
back-etched portion 145, discussed above with reference to FIG.
1.
[0033] The lid 150 is attached to the combined lead frame 110 and
acoustic horn 120 in block 320. The lid 150 is previously formed,
for example, using a molding process similar to the transfer
molding process of the acoustic horn 120, described above with
reference to block 314. As shown in FIG. 4 with respect to lead
frame package 100b, the lid 150 fits over the lead frame 110 and
the acoustic horn 120, forming an encasement containing the
transducer die 140. The terminal leads 111-114 extend from the
encasement to enable electrical contact with external circuits. In
an embodiment, the lid 150 is mechanically attached to the base
portion 122 of the acoustic horn 120 by press fitting, for example.
Alternatively or in addition, the lid 150 may be attached to the
base portion 122 using an epoxy adhesive, for example, creating a
hermetically sealed environment. Of course, other means of
attachment, such as soldering, clamping, and the like, may be
incorporated without departing from the scope of the present
teachings.
[0034] In block 322, the terminal leads 111-114 are cut (and
trimmed), removing the corresponding lead frame package, e.g., lead
frame packages 100a and 100b, from the lead frame alignment tracks
180 and 190. The separate lead frame packages may then be subject
to post fabrication processes, such as quality, electrical and/or
acoustical testing and packing for shipment, for example.
[0035] Accordingly, various embodiments provide assembled lead
frame packages that include encased transducer dies, such as MEMS
transducers, and integrated acoustic horns. The acoustic horns may
have any of a variety of shapes, used for amplifying acoustic
signals, forming/shaping an acoustic beam of the acoustic signals
and/or providing impedance matching in accordance with application
specific design requirements of various implementations, as would
be apparent to one skilled in the art.
[0036] The various components, materials, structures and parameters
are included by way of illustration and example only and not in any
limiting sense. In view of this disclosure, those skilled in the
art can implement the present teachings in determining their own
applications and needed components, materials, structures and
equipment to implement these applications, while remaining within
the scope of the appended claims.
* * * * *